Novel, acidic, and cold-adapted glycoside hydrolase family 8 endo-β-1,4-glucanase from an Antarctic lichen-associated bacterium, Lichenicola cladoniae PAMC 26568.

Autor: Kim DY; Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea., Kim J; Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea., Lee YM; Division of Life Sciences, Korea Polar Research Institute, Incheon, South Korea., Byeon SM; Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.; Department of Biological Science, Daejeon University, Daejeon, South Korea., Gwak JH; Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea., Lee JS; Biocenter, Gyeonggido Business and Science Accelerator (GBSA), Suwon, South Korea., Shin DH; Insect Biotech Co. Ltd., Daejeon, South Korea., Park HY; Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.
Jazyk: angličtina
Zdroj: Frontiers in microbiology [Front Microbiol] 2022 Jul 14; Vol. 13, pp. 935497. Date of Electronic Publication: 2022 Jul 14 (Print Publication: 2022).
DOI: 10.3389/fmicb.2022.935497
Abstrakt: Endo-β-1,4-glucanase is a crucial glycoside hydrolase (GH) involved in the decomposition of cellulosic materials. In this study, to discover a novel cold-adapted β-1,4-D-glucan-degrading enzyme, the gene coding for an extracellular endo-β-1,4-glucanase (GluL) from Lichenicola cladoniae PAMC 26568, an Antarctic lichen ( Cladonia borealis )-associated bacterium, was identified and recombinantly expressed in Escherichia coli BL21. The GluL gene (1044-bp) encoded a non-modular polypeptide consisting of a single catalytic GH8 domain, which shared the highest sequence identity of 55% with that of an uncharacterized protein from Gluconacetobacter takamatsuzukensis (WP_182950054). The recombinant endo-β-1,4-glucanase (rGluL: 38.0 kDa) most efficiently degraded sodium carboxymethylcellulose (CMC) at pH 4.0 and 45°C, and showed approximately 23% of its maximum degradation activity even at 3°C. The biocatalytic activity of rGluL was noticeably enhanced by >1.3-fold in the presence of 1 mM Mn 2+ or NaCl at concentrations between 0.1 and 0.5 M, whereas the enzyme was considerably downregulated by 1 mM Hg 2+ and Fe 2+ together with 5 mM N -bromosuccinimide and 0.5% sodium dodecyl sulfate. rGluL is a true endo-β-1,4-glucanase, which could preferentially decompose D-cellooligosaccharides consisting of 3 to 6 D-glucose, CMC, and barley β-glucan, without other additional glycoside hydrolase activities. The specific activity (15.1 U mg -1 ) and k cat / K m value (6.35 mg -1 s -1 mL) of rGluL toward barley β-glucan were approximately 1.8- and 2.2-fold higher, respectively, compared to its specific activity (8.3 U mg -1 ) and k cat / K m value (2.83 mg -1 s -1 mL) toward CMC. The enzymatic hydrolysis of CMC, D-cellotetraose, and D-cellohexaose yielded primarily D-cellobiose, accompanied by D-glucose, D-cellotriose, and D-cellotetraose. However, the cleavage of D-cellopentaose by rGluL resulted in the production of only D-cellobiose and D-cellotriose. The findings of the present study imply that rGluL is a novel, acidic, and cold-adapted GH8 endo-β-1,4-glucanase with high specific activity, which can be exploited as a promising candidate in low-temperature processes including textile and food processes.
Competing Interests: D-HS was employed by Insect Biotech Co. Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Kim, Kim, Lee, Byeon, Gwak, Lee, Shin and Park.)
Databáze: MEDLINE
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